Posted by: Didapper PJ15 JAN 2014
In my Christmas miscellany article about the medicinal uses of urine and its constituents (PJ 2013;291:658), I mentioned that the urea used in products for skin conditions is now synthesised rather than obtained from biological sources.
For nearly 30 years after its isolation and identification in 1799, urea could be obtained only from urine or kidneys. But in 1828 Friedrich Wöhler, a German chemist, made it by accident when reacting silver cyanate with ammonium chloride in an attempt to form ammonium cyanate. He succeeded, but the atoms of the unstable inorganic compound rapidly rearranged themselves to form urea.
Wöhler’s synthesis of an organic compound from inorganic chemicals without involving living organisms is widely regarded as the starting point of modern organic chemistry. He has been dubbed “the father of organic chemistry”.
The synthesis of urea is not Wöhler’s only claim to fame. With Justus Liebig, he also showed that organic radicals can behave like elements and replace them in chemical compounds. And his research in inorganic chemistry led to new methods of preparing beryllium, boron, silicon, titanium and phosphorus. He also found an improved production method for pure aluminium and was the first to determine its chemical and physical properties — density, electrical conductivity, corrosion resistance, combustibility, etc.
Wöhler’s synthesis of urea was the beginning of the end for the centuries-old doctrine of vitalism, which maintained that living organisms contain some vital force that is absent from inanimate matter, and therefore that organic substances can only be made by living things.
It has been claimed that Wöhler set out to disprove vitalism, but he did not. He was himself a vitalist and his accidental discovery unsettled him. In a letter to his mentor Jöns Jakob Berzelius, he described his discovery as “the great tragedy of science, the slaying of a beautiful hypothesis by an ugly fact”.